JPS5544267A - Color television receiver - Google Patents

Abstract

PURPOSE: To correct the index signal surely with a simple constitution, by detecting the phase shift of the original index signal through the use of chroma signal while supplying the original index signal to the variable phase shifter and controlling the amount of shift of the phase shifter through the detected output.

CONSTITUTION: The light 13 emitted when spotting the electron beam 12 from the panel inside of the color receiving tube 11 of beam index system, is detected with the photo detector 14 placed external the funnel. Next, the color difference signals ER-EY, EG-EY, EB-EY obtained through the demodulation of this light are fed to the matrix circuit 21, and the luminance signal EY is fed to the circuit 21 to cause the primary color signals ER, EG, EB to the circuit 21. After that, this is fed to the switch circuits 22R, 22G, 22B and the output of the detector 14 is fed to the band pass filter 23 to pick up the original index signal. Further, this is fed to the PLL circuit 25 via the variable phase shifter 24 to produce the signal in frequency 3f₁. Simultaneously, the color differnece signal is fed to the subtractor 27 and the phase sifter 24 is controlled with this output.

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